Call center and other computerized telephony operations in the past have sometimes economized on network infrastructure by sharing physical communications connections. In these arrangements, a company or group of separate companies may for example publicize multiple (800) or other numbers for various types of customer support or other operations. For instance, a large financial institution may offer one (800) for retail banking accounts, another (800) number for mutual fund clients and another (800) for brokerage trading. While those numbers may be separate, each number may be channeled over long distance or other networks to one physical trunk or connection, to economize of network costs and maintenance.
When multiple (800) or other numbers are logically shared over common network resources, it has been known in the past to identify calls coming in over one number or another using the dialed number identification service (DNIS). For instance as illustrated in FIG. 1, a call arriving over a long distance network may be managed by a service control point (SCP) or other resource, under the signaling system 7 (SS7) or other architecture. The SCP may detect or receive the caller's dialed number (DN) such as a 10-digit (800) number, the number from which the call is being made via automatic number identification (ANI), caller ID or other services, and use that information to deliver the call to an appropriate destination.
That destination may be or include, for example, an automatic call distributor (ACD), an interactive voice response (IVR) unit, or other destination or resource. That ACD or other hardware or software may be correspondingly programmed or equipped with tools or applications to service specific types of calls, such as account inquiries, transactions, subscription or other inquiries or support. The call may be delivered to that ACD or other destination over common telephone, data or other links, along with other calls, for instance over T-1 or other lines.
To ensure that the call which is being sent over the common lines or connections is properly identified and delivered to the most appropriate ACD, the SCP or other controller may employ the known DNIS system to identify the dialed number from which the call originated. According to that system, the SCP or other controller may transmit call-identifying tag or other information based on or related to the originally dialed number to the destination ACD. That DNIS tag, label or other identifying information may be or include, for instance, a 3 or 4-digit code appended to or associated with the destination number. The DNIS information may also be encoded in other formats.
The DNIS information may be transmitted to the ACD or other destination through in-band signaling in the voice channel. Typically that information is transmitted using dual tone multiple frequency (DTMF) or other tones or signals through the voice channel. Once the ACD or other destination has decoded the DNIS digits, that resource can distribute or process the call according to the dialed (800) or other numbers, for instance to invoke a voice menu, distribute the call to a customer support representative (CSR), or perform other processing.
While the conventional DNIS system functions adequately for the delivery of identified calls in environments including comparatively low-volume environments, there are still difficulties in ensuring DNIS-based call distribution in other contexts. One challenge is the delivery of DNIS-labeled calls in a high-volume environment. This problem arises in one regard because the number and capacity of communications links through which the call may be connected to the ACD or other destination may be limited. For instance, the network operator may lease T-1 or other lines and not be able to readily add capacity to those lines, when a comparatively greater call volume occurs.
Further, the SCP or other controller which associates a DNIS number or tag with a call to transmit in-band with the call is conventionally configured with a fixed translation table, so that given (800) numbers are always transmitted to given ACD or other resources using given DNIS numbers or tags. The total number of those assignments may therefore be fixed, and even when there may be on the order of hundreds of available DNIS numbers or associated labels or tags, call centers which experience hundreds or thousands of calls per minute may exceed the available set of DNIS/destination assignments, communications links or both. In those cases calls must remain in the default queue until DNIS and other resources free up, causing delays in response time and other customer metrics, or causing a call drop if the default queue is not suitably configured. Other problems in dialed number-based call distribution schemes exist.